1. Field of the Invention
The invention concerns a device which is manually operable to shut off the flow of a fluid through a conduit and is especially useful for minimizing the amount of chloroflorocarbon refrigerants that escape to the atmosphere each time a refrigeration or air conditioning system is serviced. The invention is also directed to apparatus and method which employ one or more of the shut-off devices.
2. Description of Background Information
Current refrigeration and air conditioning service techniques include the use of a manifold which commonly has three refrigeration lines or hoses connected thereto. One line is connected through the manifold to a low pressure gauge and is used in servicing the low pressure side of a refrigeration/air conditioning system. A second line is connected through the manifold to a high pressure gauge and is used in servicing the high pressure side of a refrigeration/air conditioning system. A third line is connected to a port which commonly connects the ports in the manifold leading to the high and low pressure lines. The third line is used for connection to refrigerant or some other pressurized source, or a vacuum source.
Alternatively, a simpler device is commonly used for charging air conditioning/refrigeration systems which includes only one refrigeration line with a fitting for connection to a pressurized refrigerant source. This device may or may not include a pressure gauge.
In either case, the ends of the lines which are not connected to the manifold or fitting, i.e., the ends which are distal to the apparatus, do not currently include flow control mechanisms. Flow control is performed by means of high pressure and low pressure valves at the manifold. Consequently, whenever any of the aforementioned three lines are connected to a refrigeration or air conditioning system, the lines must be bled to purge the air from the lines so as to avoid contamination of the refrigeration system with air. This necessitates the release of a small amount of refrigerant to the environment each time a line is bled. Even more significant, when the lines are removed from the system after servicing, the entire volume of refrigerant contained within the lines escapes to the atmosphere, since there are currently no shut-off mechanisms at the distal ends of the refrigeration lines.
Chlorofluorocarbons, such as Freon, are the most common refrigerants in use today. Further, it has been hypothesized and it is becoming increasingly more evident that chlorofluorocarbons are a major cause of the degradation of the ozone layer of the atmosphere. Consequently, since the ozone layer's integrity is vital for the protection of the surface of the earth from damaging amounts of solar radiation, the necessity for reducing the amount of release of chlorofluorocarbons to the atmosphere is becoming more and more critical. Further, unnecessary wasting of chlorofluorocarbons can be expensive. The cost of R-12, for example, has recently doubled and will likely continue to increase as the use of chlorofluorocarbons tends to be phased out.
As other resources become increasingly scarce, and thus more valuable, the avoidance of unnecessary escape or spillage of other gases or liquids is also desirable. For example, water hoses or any hose in which a length thereof is disconnected from a particular apparatus is susceptible to an unnecessary release of water or other fluid therefrom upon such disconnection. Such unnecessary release can result merely in an unnecessary waste of the fluid or the inconvenience of a spillage thereof, for example, or, in the case of caustic fluids, for example, an additional hazard relating to such release.